Wireless inductive coupling assembly for a heated glass panel

ABSTRACT

A wireless inductive coupling assembly for a heated glass panel assembly is provided that includes a metal oxide coated glass panel with a panel frame, an opening frame that cooperates with the coated glass panel frame to allow the panel to cover a panel opening, a receiving coil that is positioned in the panel frame and that is wired to the panel, and a sending coil that is positioned in the opening frame and that is wired to an electrical power source. When the electrical power source supplies electrical power to the sending coil, the sending coil wirelessly induces an electrical current in the receiving coil, which causes the dielectric panel to provide heat.

FIELD OF THE INVENTION

The present invention relates to electrical connectivity for a heateddielectric unit. More particularly, the present invention relates toelectrical connectivity for a heated glass panel by way of a wirelesselectrical inductive coupling assembly.

BACKGROUND OF THE INVENTION

Those skilled in the art know that electrical power is utilized toproduce heat in dielectric panels (a.k.a., units), for example, glass,ceramic, or glass-ceramic panels, that have an electrically conductivethin-film coating, which typically is non-magnetic, disposed thereon. Inthe past, film deposition techniques, such as those used in spraycoatings, were not precise, which resulted in non-uniform coatings andconsequently imprecise heating. Recently, the deposition of, forexample, metal oxide coatings has improved through the use of chemicalvapor deposition (CVD) processes.

Examples of heated glass applications that have utilized these coatingsover the last thirty years are commercial refrigerator and freezer doorsin supermarkets, where a tin oxide coating is disposed on one of theinterior surfaces of an insulating glass (IG) panel and where anelectric current is dissipated in the tin oxide coating to provide heatto raise the glass temperature above the dew point. On such doors, theheat eliminates the formation of condensation so that employees andcustomers can view the refrigerator/freezer contents after individualshave opened and closed the doors.

Non-uniform coatings and traditional electrical control connectionmethods, however, result in wasted energy, produce hot and cold spots onthe glass, and can result in safety hazards should the glass break andexpose the current-carrying film. In order to provide the electricalpower to such heated dielectric panels, electrical wires are, typically,directly connected to bus bars that are disposed on the heateddielectric panels or electrical wires are directly connected to metaltabs that are disposed on these bus bars.

Often, electrical wires from, for example, an electrical power source,are routed by pathways, for example, conduit, raceways, and/ordoor/window sashes and jambs, to the heated dielectric panels.Potentially, direct wiring to the bus bars or the metal tabs can beunyielding and unsafe.

As they apply to building applications (i.e., windows, doors, skylights,and radiant heater panels) in the U.S., the methodologies associatedwith electrical wiring are established by the National Electrical Code(NEC). Per the NEC, any wiring having voltages greater than 42 volts isdesignated as class I wiring, which must be protected from accidentaldamage and must have all interconnections, splices, etc. inside anapproved junction box (j-box). Hence, it is not possible to directly runwiring, for purposes of carrying line voltage and usable power, tooperable windows and doors, and still comply with NEC requirements.

In addition, most code officials and inspectors require that anyinstalled electrical device must have Underwriter Laboratory (UL) orequivalent approval. UL also will not approve exposed wiring or exposedconnectors at 110-250 volts.

One means of interconnecting wiring, which has been used in the past, isto utilize pin connectors with a safety interlock, but there areconcerns regarding the long term reliability of such connectors, sincecorrosion of the connectors can result in electrical arcing at theconnectors. Also, if the safety interlock is bypassed or defeated,electrical shock potential can result.

Regarding connectivity to heated glass panels, U.S. Pat. No. 5,852,284to Teder et al. utilizes a capacitor to electrically couple to a heatedglass door/panel, where the coupling is achieved by “adjusting” powerfrom an electric power source by way of the capacitive reactance of anRC (resistor/capacitor) circuit. Then, Teder directly connects thecapacitor, whose geometry must be considered when being mounted in theframe/sash of a door/window or in the space between two panes of glass,to the heated glass door/panel. In addition, the value (in farads orportions thereof), plate size, spacing, and dielectric material of thecapacitor must be specifically chosen for the glass size and powerlevel.

On the other hand, U.S. Pat. No. 5,529,708 to Palmgren et al. teachesthe use of electrical radio frequency energy in the range of 2.5-8 MHz,where a non-magnetic substrate has a magnetic coating disposed thereon,to provide an inductive heater. However, Palmgren is silent on theutilization of non-magnetic coatings that are typically found in heatedglass applications and which are discussed herein. Hence, neither Tedernor Palmgren overcome the above stated shortcomings associated withdirectly connecting a power source to a heated glass panel.

U.S. Pat. No. 5,821,507 to Sasaki et al. provides an electric cookerthat utilizes a work coil to generate an inductive flux that heats ametal heating member. An insulator separates the work coil from themetal heating member and a wire mesh is used to support a food item. Asillustrated in Sasaki's FIGS. 11 and 13, alternatively, a pot or pan maybe used to support the food item, where electrical power is transmittedfrom a first work coil to an induction coil, which in turn supplieselectrical power to a second work coil. The second work coil directlygenerates eddy currents in the bottom portion of the metal pan, thusheating the food item by way of eddy current loss.

Still, it would be advantageous to seek an indirect electricalconnectivity means to wirelessly communicate electrical energy to aheated glass panel assembly that is electrically safe, energy efficient,and meets or exceeds NEC and UL standards.

SUMMARY OF THE INVENTION

The present invention relates to a wireless inductive coupling assemblyfor a heated dielectric panel assembly. The wireless inductive assemblycomprises a dielectric panel that has a metal oxide coating disposedthereon and a panel frame disposed on at least a portion of a peripherythereof. The wireless inductive coupling assembly further comprises anopening frame, where the opening frame cooperates with the panel frameto allow the dielectric panel to at least partially cover a panelopening.

Still further, the wireless inductive coupling assembly comprises areceiving coil and a sending coil. The receiving coil is disposed in thepanel frame, while the receiving coil is in electrical communicationwith the dielectric panel. On the other hand, the sending coil isdisposed in the opening frame, where the sending coil is in wirelessinductive electrical communication with the receiving coil, and wherethe sending coil is in electrical communication with an electrical powersource. Thus, when electrical power from the electrical power source iscommunicated to the sending coil, an electrical current is induced inthe receiving coil, which in turn causes the panel to generate heat.

Further advantages of the present invention will be apparent from thefollowing description and appended claims, reference being made to theaccompanying drawings forming a part of a specification, wherein likereference characters designate corresponding parts of several views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of a wireless inductive coupling assembly inaccordance with the present invention; and

FIG. 2 is an electrical circuit schematic of the wireless inductivecoupling assembly of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The present invention, as illustrated in FIG. 1, relates to a wirelessinductive coupling assembly 10 that comprises a heated dielectric panel15. The heated dielectric panel assembly 15 comprises a dielectric panel20 (a.k.a, a dielectric sheet), where the dielectric panel 20 has atleast two bus bars 26 (see FIG. 2) disposed on a metal oxide coating 11that in turn is disposed on a dielectric substrate 20 a. The heateddielectric panel assembly 15 also has a panel frame 12 disposed on atleast a portion of a periphery 13 thereof. The wireless inductivecoupling assembly 10 further comprises an opening frame 14, where theopening frame 14 cooperates with the panel frame 12 to allow the heateddielectric panel assembly 15 to cover a panel opening 16.

Still further, the wireless inductive coupling assembly 10 comprises areceiving coil 17 and a sending coil 18. The receiving coil 17 isdisposed in the panel frame 12, where the receiving coil 17 is inelectrical communication with the metal oxide coating 11 on thedielectric panel 20, via the bus bars 26. On the other hand, the sendingcoil 18 is disposed in the opening frame 14, where the sending coil 18is in wireless inductive electrical communication with the receivingcoil 17, and where the sending coil 18 is further in electricalcommunication 22 (that includes wires, conduit, and the like) with anelectrical power source 24.

In order to control and to supply power to the coils 17,18 and thedielectric panel 20, the electrical power source 24 may comprise asolid-state controller (as used herein, the solid-state controller is anelectronic device that comprises a microprocessor), a power supply,sensors, a triac circuit, and input/output circuitry as that containedin U.S. Application Publication No. 2003/0127452 to Gerhardinger et al.,which is incorporated herein by reference in its entirety. See, forexample, FIGS. 1A, 8A (insulating glass), 9 (laminate) of the '452Publication.

Thus, when electrical power from the electrical power source 24 iscommunicated to the sending coil 18, an electrical current is induced inthe receiving coil 17, which in turn causes electrical current I (asshown in FIG. 2) to be provided to the panel 20 for generating heat.

Hence, in the present invention, heating is not directly provided by aninductive flux from the coils 17,18. Instead, heating is provided by thepanel 20, which utilizes electrical current I from the receiving coil17.

In the present invention, the coating 11 may be a chemical vapordeposited metal oxide, like tin oxide, where the metal oxide is renderedelectrically conductive by the inclusion of a dopant, such as fluorine,indium, and antimony. As such, the conductive thin-film coating 11 maybe precisely and uniformly disposed on a suitable substrate 20 a at athickness of one micron or less.

The metal oxide may also possess low emissivity (low-E) thermalproperties, such that much of the heat energy generated by theconductive coating is radiated into the dielectric sheet and then suchheat energy is radiated away from the dielectric sheet, which may betransparent, opaque, or translucent.

Subsequently, objects and/or people are beneficially heated by way ofheat radiation of such heat energy from the heated dielectric materialor by way of convection of heated air. These processes result in littleheat being wasted (see U.S. Pat. Nos. 7,039,304 and 7,041,942 toGerhardinger et al., which are incorporated herein by reference in theirentirety).

Although FIG. 1 illustrates the present invention as generallyrectangular in shape, the present invention is not limited by the shapeof the various structures, for example, items 12,14,20. It is, however,within the spirit and scope of the present invention that the shape ofthe various structures 12,14,20 might, for example, be square,elliptical, circular, or irregular. The dielectric substrate maycomprise glass, glass-ceramic, or ceramic. The dielectric panels may bemade of Thermique™ heated glass panels, which are a product ofEngineered Glass Products, LLC of Chicago, Ill. The heated dielectricpanel assembly 15 with receiving coil 17 and panel frame 12 may beseparable from the opening frame 14.

Also, the above described dielectric panel 20 may be embodied, forexample, as an architectural panel, a commercial panel assembly (forexample, a commercial refrigerator or freezer door), an automotive panelassembly, or an appliance panel assembly, to name just a few. Therefore,depending on the embodiment of the present invention, the reference item25 might be a building member when the heated dielectric panel assembly15 is an architectural panel with a sash (panel frame) and a jamb(opening frame), might be a food freezer when the heated dielectricpanel assembly 15 is a commercial panel, might be a vehicle body memberwhen the heated dielectric panel assembly 15 is an automotive panel(e.g., a rear window or a mirror), or might be a cooktop when the heateddielectric panel assembly 15 is an appliance panel (as in U.S. Patents'304 and '942).

Another example of an appliance panel assembly is a food item holdingbin in a restaurant, where dielectric panels 20 could be utilized asheated glass doors to keep, for example, hamburger buns warm prior toutilizing the buns in hamburger sandwiches. Also, the variousembodiments of the present invention may be in the form of laminatedstructures and/or insulating glass structures.

It has been found, while operating the electrical power source 24 attypical power line AC frequencies (i.e., 50/60 Hz) to heat thedielectric panel 20, that an efficiency power coupling of only 50% orless is obtained. In addition, when large ferromagnetic cores areutilized, the coils 17,18 undesirably vibrate and magnetically coupletogether when the coils 17,18 are energized.

However, while operating the electrical power source 24 at an ACfrequency in the range of 20-40 kilohertz (i.e., nominally at 30 KHz) topower the dielectric panel 20, it has been found in the instantinvention that an efficiency power coupling of 92% or higher isobtained. This is achieved by the wireless inductive coupling assembly10, when the coils 17,18 are separated by the combined outsidethicknesses of the panel frame 12 and the opening frame 14.

Although the present invention is not limited to any particular output,the following example is given as an insight to providing a 500 wattwireless inductive coupling assembly. A glass panel 20 with a coating 11that is rated at a maximum of 25 watts per square foot, may be utilizedin a typical heated slider door that measures seven feet by three feet(i.e., 21 square feet). Therefore, 25 watts per square foot times 21square feet would provide approximately 500 watts for heating thesliding door. Of course, higher power applications would simply use alarger power supply and would cost more.

In contrast to the efficiency power coupling of 92% or higher that isobtained in the present invention, Sasaki, who was mentioned earlier,utilizes three coils (i.e., a first work coil, an induction coil, and asecond work coil) to directly inductively heat a metal pan by way ofinductive flux “eddy current losses.”

Also, due to the inducement of current flow (i.e., between the coils17,18) in the present invention, electrical shock hazard is virtuallyeliminated and the wiring to the heated dielectric panel assembly 15 issimplified, thus electrically isolating the electrical power source 24from the dielectric panel 20. Since there are no wires and electricalcontacts between the panel frame 12 and the opening frame 14, electricalreliability of the heated dielectric panel assembly 15 is greatlyimproved over existing heated glass assemblies and NEC and UL standardsare met or exceeded.

Using the above-stated structure of the present invention, it ispreferable that a non-iron core 27 (i.e., non-magnetic) be utilized tocouple the coils 17,18, where the core 27 may comprise, for example, aferrite (which also minimizes the size of the coils 17,18) or where anair core 27 may be utilized. Further, one or more of the coils 17,18 maybe wound with Litz wire (which is known to be comprised of very finemulti-strand copper that basically eliminates magnetic coupling), andthe panel frame 12 and the opening frame 14 are not comprised ofiron/steel (i.e., not comprised of magnetic material).

Hence, as illustrated in FIG. 2, the outside thicknesses of the panelframe 12 and the opening frame 14 are part of the non-magnetic core 27.Further, the coils 17,18 could be essentially identical in structure andcomposition, and the coil geometry is, generally, that of a flat loopwhich is embedded in, possibly, a polymer or epoxy (not shown) tomaintain the form of the loops.

The electrical power source 24, when embodied as a microprocessorutilizing software, may incorporate features to detect proper currentdraw by the dielectric panel 20 and, therefore, “know” when the coils17,18 are aligned. For example, if a window/door 15 is opened/closed,then the electrical power source 24 would not attempt to power up thesending coil 18 unless the receiving coil 17 is in the proximity of thesending coil 18. Furthermore, the electrical power source 24 mayregulate the power output to respond to faults (such as sensing brokenglass or bad connectors), act as a fail-safe feature so as to insuresafe operation under varying conditions, and to regulate heateddielectric panel assembly temperatures similar to that described in U.S.Application Publication '452 and as illustrated in FIG. 1A of the '452Publication.

FIG. 2 depicts an electrical circuit of the present invention where atleast two bus bars 26 are disposed thereon, and are in electricalconnectivity with, the metal oxide coating 11. The metal oxide coating11 is connected across the receiving coil 17, which is shown disposedwithin the panel frame 12. The sending coil 18 is shown in wirelessinductive electrical communication with the receiving coil 17, where thesending coil 18 is disposed within the opening frame 14, thusillustrating the electrical isolation of the present invention. Thesending coil 18 is also shown in electrical communication with theelectrical power source 24.

As discussed above, the arrangement of the coils 17,18 of the presentinvention may not be applicable in ferrous (e.g., steel) frames 12,14.However, frames 12,14 of aluminum, wood, polyvinylchloride (PVC), andthe like would be applicable.

Thus, the present invention provides an indirect electrical connectivitymeans to communicate electrical energy to a heated glass panel assembly15 that is reliable, electrically safe, and energy efficient.

In accordance with the provisions of the patent statutes, the principlesand modes of operation of this invention have been described andillustrated in its preferred embodiments. However, it must be understoodthat the invention may be practiced otherwise than specificallyexplained and illustrated without departing from its spirit or scope.

1-27. (canceled)
 28. A wireless inductive coupling assembly, comprising:a dielectric panel, wherein the dielectric panel is transparent; anopening frame for helping allow the dielectric panel to at leastpartially cover a panel opening; a receiving coil in electricalcommunication with a coating of the dielectric panel; and a sending coilin wireless inductive electrical communication with the receiving coil,and being in electrical communication with an electrical power source;wherein electrical power from the electrical power source, by way of thesending coil and the receiving coil, is utilized by the dielectric panelfor heating the dielectric panel.
 29. The wireless inductive couplingassembly of claim 28, further comprising a second dielectric panel,wherein the dielectric panels are laminated to one another.
 30. Thewireless inductive coupling assembly of claim 28, wherein the dielectricpanel comprises glass.
 31. The wireless inductive coupling assembly ofclaim 28, wherein the dielectric panel is separable from the openingframe.